A conventional image forming device includes a main casing within which a process unit is detachably accommodated. In such an image forming device, the process unit is configured of a drum cartridge and a developing cartridge. The drum cartridge is detachably loadable in the main casing and includes a photosensitive drum. The developing cartridge is formed with a toner chamber for accommodating toner therein and is detachably mounted on the drum cartridge. In other words, the process unit can be separated into the drum cartridge and the developing cartridge, and the process unit as a whole is detachably loadable in the main casing of the image forming device.
The developing cartridge includes a developing roller for supplying the accommodated toner to the photosensitive drum. The drum cartridge has a drum frame on which a lever is provided as a pressing member so that the developing roller can be pressed against the photosensitive drum.